1. When we are sorting the numbers we will first find the number of digits in the biggest number.

2. If there are N digits in the biggest number then we will need to perform N number of pass.

3. We will pad the remaining numbers with leading zeros so they all have N digits.

4. Then we will take 10 buckets labeled 0 to 9 and sort the numbers.

Time Complexity : O(N*n)  where N is the digits of the biggest number, and n is the length of the array.

Space Complexity: O(1), it will take 10 buckets.

https://www.youtube.com/watch?v=YXFI4osELGU

Radix Sort